The intake system of a racing engine plays a crucial role in determining its performance,particularly in terms of volumetric efficiency,power output,and throttle response.According to Formula Society of Automotive Eng...The intake system of a racing engine plays a crucial role in determining its performance,particularly in terms of volumetric efficiency,power output,and throttle response.According to Formula Society of Automotive Engineers(FSAE)regulations,the engine intake systemmust incorporate a 20mmdiameter flow-limiting valve within the intake manifold.This restriction significantly reduces the airflow into the engine,leading to a substantial drop in power output.To mitigate this limitation,the intake system requires a redesign.In this study,theoretical calculations and one-dimensional thermodynamic simulations are employed to determine the optimal parameters for the intake system.A numerical simulation of the intake system’s flow field is then conducted to refine its structure and layout.Finally,experiments are performed on an engine equipped with the optimized intake system,and its feasibility is evaluated based on experimental results.Thefindings indicate that the maximumengine torque increases from56.36 to 59.91 N⋅m,while the maximum power output rises from 59.16 to 63.94 kW.To further enhance performance and adaptability across different competitions,a variable-length intakemanifold control system is also designed,improving both power delivery and overall operational stability of the racing car.展开更多
In some competitions the rules clearly state that all participating cars must install a restrictor valve structure in the intake system of the engine.The intake air volume of the engine is considerably affected due to...In some competitions the rules clearly state that all participating cars must install a restrictor valve structure in the intake system of the engine.The intake air volume of the engine is considerably affected due to the existence of such a valve.Indeed,a small interface diameter through which gas flows can lead to considerable flow resistance and loss.In this study,a four-cylinder engine for FSC racing is analyzed using a combined method based on numerical simulation and experiments.The analysis reveals that the main factors affecting the intake air volume are the intake manifold and the volume of the resonance chamber.The influence of such factors is assessed using a single variable method and an optimal model and parameters are obtained accordingly.Comparison of different results show that the maximum torque for the optimized system is increased from the original 42.6 N·m to 46.9 N·m,thus demonstrating an increase of 10.6%.These findings provide a theoretical basis for the design of the intake system and the improvement of engine performance.展开更多
To find out and improve the flow characteristics inside the intake system of cylinder head,the application of computational fluid dynamics(CFD)in the evaluation and optimization of the reconstructed intake system base...To find out and improve the flow characteristics inside the intake system of cylinder head,the application of computational fluid dynamics(CFD)in the evaluation and optimization of the reconstructed intake system based on slicing reverse method was proposed.The flow characteristics were found out through CFD,and the velocity vector field,pressure field and turbulent kinetic energy field for different valve lifts were discussed,which were in good agreement with experimental data,and the quality of reconstruction was evaluated.In order to improve its flow characteristic,an optimization plan was proposed.The results show that the flow characteristics after optimization are obviously improved.The results can provide a reference for the design and optimization of the intake system of cylinder head.展开更多
The goal of this study is to develop an airflow meter sensor for vehicle intake system detection in internal combustion engines. The study uses micro-electromechanical process technology to develop a hot-film flow met...The goal of this study is to develop an airflow meter sensor for vehicle intake system detection in internal combustion engines. The study uses micro-electromechanical process technology to develop a hot-film flow meter with an alumina substrate and platinum film heater;the hotline method is used to create a micro airflow anemometry meter sensor relying on variations in resistance of the platinum film corresponding to different wind velocity at the set temperatures. The micro-sensor is less bulky and simpler structure than ordinary meters, and its small size enables it to provide good sensitivity and measurement precision. The alumina plate used in this study is produced by polishing an alumina substrate, a platinum film is then deposited on the plate to complete the micro-heater used in the sensor. Resistance on the sensor side varies as gas flows through the sensor, and the instrument determines airflow velocity on the basis of the changes in resistance caused by gas flow differences. Airflow velocity form 10 m/s to 60 m/s are used to test. Resistance displays a regular slope, indicating the relationship between airflow velocities varies remain predictable throughout the sensing range. Therefore, the sensor can achieve its airflow measurement purpose completely.展开更多
Industry and energy continue to require piston engines(PICE)at a high level worldwide.Therefore,science and technology must urgently work on improving the PICE working cycle.Improving the quality of the intake process...Industry and energy continue to require piston engines(PICE)at a high level worldwide.Therefore,science and technology must urgently work on improving the PICE working cycle.Improving the quality of the intake process of theworking fluid into the cylinder is one of the most effective ways to improve the operational performance of PICE.The purpose of the study was to assess the impact of various cylinder head(CylH)designs on the gas-dynamic and heat-exchange qualities of air flows within an engine model’s intake system.Three different CylH designs were studied:the basic configuration and upgraded cylinder heads with a square valve and a square valve port.These designs are innovative.Laboratory conditions were used to conduct the studies for stationary air flow.The experiments covered the range of Reynolds numbers from 8500 to 96,000.The intake system’s gas dynamics and heat transfer were determined using the thermal anemometry method,which was based on constant-temperature hot-wire anemometers.It has been established that the use of upgraded CylHs causes an increase in the turbulence number of flow by an average of 13.5%.Additionally,itwas found that the increase in the turbulence number of flowin the cylinder is about 19%when installing new CylH designs.It was shown that therewas an increase in the heat transfer coefficient in the intake pipe by 10%–40%when installing modernized CylH designs in the intake system.The article focused on the problems of increasing the turbulence level and intensifying the heat transfer of stationary air flow in the intake system,specifically in PICEs.The study’s findings are novel in the areas of applied gas dynamics and PICEs.展开更多
Based on energy conservation equation and Darcy＇s law, a model of beach well infiltration intake system applied in a seawater source heat pump system was established. The model consists of the seawater seepage and th...Based on energy conservation equation and Darcy＇s law, a model of beach well infiltration intake system applied in a seawater source heat pump system was established. The model consists of the seawater seepage and the heat transfer process. A porous medium model in a software named FLUENT was applied to simulate the seepage and the heat transfer process. This model was also validated by field experiment conducted on the seashore in Tianjin, China. The maximum relative error between simulation results and experimental results was 2.1% （less than 5%）, which was acceptable in engineering applica- tion. The porosity and coefficient of thermal conductivity of the aquifer soil were determined to be 0.49 W/（m. K） and 1.46W/（m.K）, respectively in the simulation. In addition, the influencing factors of pumping water of beach well were also analyzed. The pumping water was found to increase when the distance between the beach well and the impervious boundary becomes longer, when the distance between the beach well and the supplying water source shortens, when the diameter of the beach well enlarges, and the drawdown enlarges.展开更多
AIM： To study the association between nitrite and nitrosamine intake and gastric cancer （GC）, between meat and processed meat intake, GC and oesophageal cancer （OC）, and between preserved fish, vegetable and smok...AIM： To study the association between nitrite and nitrosamine intake and gastric cancer （GC）, between meat and processed meat intake, GC and oesophageal cancer （OC）, and between preserved fish, vegetable and smoked food intake and GC. METHODS： In this article we reviewed all the published cohort and case-control studies from 1985-2005, and analyzed the relationship between nitrosamine and nitrite intake and the most important related food intake （meat and processed meat, preserved vegetables and fish, smoked foods and beer drinking） and GC or OC risk. Sixty-one studies, 11 cohorts and 50 case-control studies were included. RESULTS： Evidence from case-control studies supported an association between nitrite and nitrosamine intake with GC but evidence was insufficient in relation to OC. A high proportion of case-control studies found a positive association with meat intake for both tumours （11 of 16 studies on GC and 11 of 18 studies on OC）. A relatively large number of case-control studies showed quite consistent results supporting a positive association between processed meat intake and GC and OC risk （10 of 14 studies on GC and 8 of 9 studies on OC）. Almost all the case-control studies found a positive and significant association between preserved fish, vegetable and smoked food intake and GC. The evidence regarding OC was more limited. Overall the evidence from cohort studies was insufficient or more inconsistent than that from case-control studies.CONCLUSION： The available evidence supports a positive association between nitrite and nitrosamine intake and GC, between meat and processed meat intake and GC and OC, and between preserved fish, vegetable and smoked food intake and GC, but is not conclusive.展开更多
To eliminate the shrinkage porosity in low pressure casting of an A356 aluminum alloy intake manifold casting, numerical simulation on fi lling and solidifi cation processes of the casting was carried out using the Pr...To eliminate the shrinkage porosity in low pressure casting of an A356 aluminum alloy intake manifold casting, numerical simulation on fi lling and solidifi cation processes of the casting was carried out using the ProCAST software. The gating system of the casting is optimized according to the simulation results. Results show that when the gating system consists of only one sprue, the fi lling of the molten metal is not stable; and the casting does not follow the sequence solidifi cation, and many shrinkage porosities are observed through the casting. After the gating system is improved by adding one runner and two in-gates, the fi lling time is prolonged from 4.0 s to 4.5 s, the fi lling of molten metal becomes stable, but this casting does not follow the sequence solidifi cation either. Some shrinkage porosity is also observed in the hot spots of the casting. When the gating system was further improved by adding risers and chill to the hot spots of the casting, the shrinkage porosity defects were eliminated completely. Finally, by using the optimized gating system the A356 aluminum alloy intake manifold casting with integrated shape and smooth surface as well as dense microstructure was successfully produced.展开更多
A 3-D numerical model for pump intake is established based on the Navier-Stokes equations with the RNG k-ε turbulence model and the VOF method to simulate the free surface. The applicability of the proposed model is ...A 3-D numerical model for pump intake is established based on the Navier-Stokes equations with the RNG k-ε turbulence model and the VOF method to simulate the free surface. The applicability of the proposed model is validated by a test case of non-symmetric pump-intake bay. The predicted locations, structures and shapes of all vortices are in good agreement with those observed in experiments, though with some differences in vorticity strengths. The flow pattern and the efficiency of five types of pump intake systems are studied. The discharge and the velocity tmiformity of the intake system are used as indices to evaluate its performance.展开更多
This paper presents a KIVA-3 code based numerical model for three-dimensional transient intake flow in the intake port-valve-cylinder system of internal combustion engine using body-fitted technique, which can be used...This paper presents a KIVA-3 code based numerical model for three-dimensional transient intake flow in the intake port-valve-cylinder system of internal combustion engine using body-fitted technique, which can be used in numerical study on internal combustion engine with vertical and inclined valves, and has higher calculation precision. A numerical simulation (on the intake process of a two-valve engine with a semi-sphere combustion chamber and a radial intake port) is provided for analysis of the velocity field and pressure field of different plane at different crank angles. The results revealed the formation of the tumble motion, the evolution of flow field parameters and the variation of tumble ratios as important information for the design of engine in-take system.展开更多
BACKGROUND A progressive reduction in the secretion of pancreatic enzymes in patients with chronic pancreatitis(CP)results in malabsorption and ultimate malnutrition.However,the pathogenesis of malnutrition is multifa...BACKGROUND A progressive reduction in the secretion of pancreatic enzymes in patients with chronic pancreatitis(CP)results in malabsorption and ultimate malnutrition.However,the pathogenesis of malnutrition is multifactorial and other factors such as chronic inflammation,alcohol excess and poor dietary intake all contribute.Patients may restrict their dietary intake due to poor appetite or to avoid gastrointestinal symptoms and abdominal pain.Whilst up to half of patients with chronic pancreatitis are reportedly malnourished,the dietary intake of patients with CP is relatively understudied and has not been systematically reviewed to date.AIM To perform a systematic review and meta-analysis of the dietary intakes of patients with CP compared to healthy controls,and to compare the dietary intake of patients with alcohol-related CP and non-alcohol-related CP.METHODS A systematic literature search was performed using EMBASE,MEDLINE,and Cochrane review on studies published between 1946 and August 30th,2019.Adult subjects with a diagnosis of CP who had undergone dietary assessment were included in the systematic review(qualitative analysis).Studies on patients with other pancreatic diseases or who had undergone pancreatic surgery were not included.Studies comparing the dietary intake of patients with CP to that of healthy controls were included in the meta-analysis(quantitative analysis).Metaanalysis was performed using Review Manager 5.3.Newcastle Ottawa Scale(NOS)was used to assess quality of studies.RESULTS Of 6715 studies retrieved in the search,23 were eligible for qualitative analysis while 12 were eligible for quantitative analysis.In the meta-analysis,the total energy(calorie)intake of patients with CP was similar to that of healthy controls[mean difference(MD):171.3;95%confidence interval(CI):-226.01,568.5;P=0.4],however patients with CP consumed significantly fewer non-alcohol calories than controls[MD:-694.1;95%CI:-1256.1,(-132.1);P=0.02].CP patients consumed more protein,but carbohydrate and fat intakes did not differ significantly.Those with alcohol-related CP consumed more mean(standard deviation)calories than CP patients with a non-alcohol aetiology[2642(1090)kcal and 1372(394)kcal,respectively,P=0.046],as well as more protein,fat,but not carbohydrate.CONCLUSION Although patients with CP had similar calorie intake to controls,studies that analysed the contribution of alcohol to energy intake showed that patients with CP consumed fewer non-alcohol calories than healthy controls.A high calorie intake,made up to a large degree by alcohol,may in part contribute to poor nutritional status in CP.展开更多
Underground mines in Arctic and Subarctic regions require the preheating of mine intake air during winter.The cold fresh air of those remote areas can be as severe as40℃ and commonly needs to be heated to around+3℃...Underground mines in Arctic and Subarctic regions require the preheating of mine intake air during winter.The cold fresh air of those remote areas can be as severe as40℃ and commonly needs to be heated to around+3℃.This extensive amount of heating is usually provided by employing large-size air heaters,fueled by diesel,propane,natural gas,or heavy oil,leading to high energy costs and large carbon footprints.At the same time,the thermal energy content of a diesel generator sets(gen-sets)exhaust is known to be one-third of the total heating value of its combusted fuel.Exhaust heat recovery from diesel gen-sets is a growing technology that seeks to mitigate the energy costs by capturing and redirecting this commonly rejected exhaust heat to other applications such as space heating or pre-heating of the mine intake air.The present study investigated the possibility of employing a simple system based on off-theshelf heat exchanger technology,which can recover the waste heat from the exhaust of the power generation units(diesel gen-sets)in an off-grid,cold,remote mine in Canada for heating of the mine intake air.Data from a real mine was used for the analysis along with environmental data of three different location-scenarios with distinct climates.After developing a thermodynamic model,the heat savings were calculated,and an economic feasibility evaluation was performed.The proposed system was found highly viable with annual savings of up to C$6.7 million and capable enough to provide an average of around 75%of the heating demand for mine intake air,leading to a payback period of about eleven months or less for all scenarios.Deployment of seasonal thermal energy storage has also been recommended to mitigate the mismatch between supply and demand,mainly in summertime,possibly allowing the system to eliminate fuel costs for intake air heating.展开更多
In order to improve the cold start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about th...In order to improve the cold start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about the partial working processes of the diesel engine, the amount of heat energy, enough to make the fuel self ignite at the end of compression process at different temperatures of coolant and intake air, was calculated. Several HY20 preheating plugs were used to heat up the intake air. Meanwhile, an electronic control system based on 8 bit micro controller unit (MCS 8031) was designed to automatically control the process of heating intake air. According to the various temperatures of coolant and ambient air, one plug or two plugs can automatically be selected to heat intake air. The demo experiment validated that the total system could operate successfully and achieve the scheduled function.展开更多
Food based approach can prove effective in improving access and availability of nutrients from foods required for daily life where most of the people depend on agriculture for their livelihood. A study on feasibility ...Food based approach can prove effective in improving access and availability of nutrients from foods required for daily life where most of the people depend on agriculture for their livelihood. A study on feasibility of Farming Systems for Nutrition (FSN) approach was undertaken from 2013 to 2018 in a few villages of Koraput district, Odisha state and Wardha district, Maharashtra state in India. Interventions were done to increase crop diversity, intercropping of pulses and cereals, promotion of seasonal vegetables and fruits along </span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">with </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">nutrition awareness. The endline survey showed increase in production diversity leading to improved household dietary diversity. This paper demonstrates the impact of FSN interventions on household nutrient intake. The results show that the intake of nutrients like protein, vitamin C, iron and calcium increased significantly in Koraput and all the nutrients including energy and vitamin A increased significantly in Wardha. The evidence shows that Farming System for Nutrition approach improves individual nutrient intake which in the long run can address the problem of undernutrition.展开更多
Equilibrium function in the cerebellum （vestibulo-cerebellar system） can deteriorate under the influence of alcohol. In the Romberg posture, the center of gravity, which was measured every 50 ms by stabilometry, app...Equilibrium function in the cerebellum （vestibulo-cerebellar system） can deteriorate under the influence of alcohol. In the Romberg posture, the center of gravity, which was measured every 50 ms by stabilometry, appeared to shift with alcohol ingestion. In the previous study, a locus in the center of gravity （stabilogram） was converted to values of statistical indices such as area of sway, total locus length, sparse density, and locus length per unit area, although these indices could not always distinguish between the stabilograms sampled from seven healthy young males in sober and intoxicated states. This measurement was made with an AMTI force plate. In this study, ＂translation error＂ was estimated in a d-dimensional embedding space in order to compare stabilograms recorded before and after the ingestion of doubly diluted brandy in 30 s （1 ≤ d ≤ 10）. The authors succeeded in validating stochastic differential equations as a mathematical model of the body sway. Although the postural control system shows different patterns in the lateral and anterior-posterior directions, the randomness in the model was preserved after alcohol intake and significantly increased in the medial/lateral direction. Visual information referred by the postural conlrol system when standing might be interfered by the effects of intoxication, which was regarded as disturbance. The possibility of detecting alcohol-ingestion-induced reduction of the equilibrium function and its recovery process are also suggested in this paper. This method is considered to be useful to diagnose the disorders of the vestibulo-cerebellar system.展开更多
Seasonal and sexual variations as well as the effect of dry feed supplement on total drinking water intake and its utilization were observed in mithun （Bosfrontalis） - a semi-wild animal found in North Eastern Hill ...Seasonal and sexual variations as well as the effect of dry feed supplement on total drinking water intake and its utilization were observed in mithun （Bosfrontalis） - a semi-wild animal found in North Eastern Hill Region （NEHR） of India. In a completely randomized design, twelve adult mithuns （B. frontalis） as per their sex and body weight were assigned in two different rearing systems （free grazing and free grazing with dry concentrate feed supplementation）, and ten growing male mithuns as per their body weight assigned in two different levels of dry concentrate feed supplementation （1.o kg and 2.0 kg dry concentrate feeds on green forage based diet） and in two different seasons （summer and winter）. It was observed that the environmental temperature had a significant effect on drinking water intake by mithuns. Drinking water consumption （per unit of body weight） was significantly （P 〈 0.05） higher in summer than in winter. Supplementation of concentrate feed on free grazing animals resulted in increase in water consumption. Total water consumption （drinking as well as performed water） was found to be 15.18 litres per 100 kg body weight by growing mithun. Feed dry matter and digestible nutrient intakes by growing mithun were observed to be increased with the increase of supplementation of dry concentrate feed. Roughage to concentrate ratio did not affect the nutrient digestibility. Mithun calves drank an average of 4.30 litres water for each kg of dry matter intake. Metabolic water was significantly （P〈0.01） increased with the increase of supplementation of concentrate feed whereas water turn over, which depends upon the body weight of the animals, did not differ significantly on offering of lower or higher level of dry feed. Faecal water loss of growing mithun was decreased with the increase in intake of concentrate feed and was estimated to be 33 - 46 % of total water intake. Excretion of water through faeces of mithun was about 3.8 % of body weight. It could, therefore, be inferred that water intake by mithun varied with seasons, rearing systems and dry feed consumption. As far as the water nutrition is concerned, it is needed to give an attention while feeding mithun in summer with dry feed supplementation under semi-intensive system of rearing.展开更多
Magnesium plays a critical role in the human's life activities and energy metabolism. This study aimed to evaluate the magnesium status of athletes via a systematic review of cross-sectional studies. A comprehensi...Magnesium plays a critical role in the human's life activities and energy metabolism. This study aimed to evaluate the magnesium status of athletes via a systematic review of cross-sectional studies. A comprehensive systematic search was conducted in PubMed, Web of Science, SPORTDiscus, Cochrane Library electronic databases, and other sources before April 5, 2021. Fourteen studies were included in the systematic review, involving 855 athletes and 521 control subjects. Serum magnesium concentration was significantly lower in athletes(mean difference(MD):-0.04 mmol/L;95% confidence interval(CI):-0.06 to-0.01;P = 0.02)in spite of significantly higher dietary magnesium intake(MD: 51.72 mg/day;95% CI: 14.62 to 88.83;P = 0.006). Meta-analysis showed that 24-h urinary magnesium excretion in athletes was significantly higher than that in the untrained population(MD: 0.76 mmol/day;95% CI: 0.11 to 1.41;P = 0.02). Despite higher total dietary magnesium intake, athletes generally have lower serum magnesium concentration and higher 24-h urinary magnesium excretion, demonstrating that the magnesium requirement of athletes is higher than the untrained population. It is necessary to carry out a dietary assessment and nutrition counseling to help athletes adopt proper diets to meet their nutritional needs in exercise.展开更多
The hydraulic and sediment deposition problems in the water intake system of a pumping house were studied by physical model. The experimental results of different working cases indicate that the sediment depositions a...The hydraulic and sediment deposition problems in the water intake system of a pumping house were studied by physical model. The experimental results of different working cases indicate that the sediment depositions at the gates, stilling basin and culverts are very few when the system was normally operated, but in the forebay of pumping house, especially in the pumping house for living water, the amount of sediment deposition sometimes is considerably large. At the front of the entry of pumping house for living water, installing a set of oblique pipes can prevent the coarse grains to enter it, the deposition amount will obviously decrease.展开更多
An monitoring and earlywarning system is proposed for marine organisms and the cause of water intake blockage is analyzed. Based onthe intelligent sensing technology, computer software and hardware technology and digi...An monitoring and earlywarning system is proposed for marine organisms and the cause of water intake blockage is analyzed. Based onthe intelligent sensing technology, computer software and hardware technology and digital signal processing technology, the buoy monitoring platformsystem is developed by internet of things technology, cloud computing and the application of large data. Remote realtime monitoring of aquatic organisms and foreign bodies is realized based on underwater acoustic detection and low light imaging technology. Data processing center is established to store, analyze and process monitoring information and display it in real time, and provide emergency decision support. Through development and test of relevant key equipments, the reliability of cold source system of nuclear power plants is improved, which effectively reduces theinfluence of marine biological invasion on security and economic operation of the units.展开更多
Lifestyle is related to many chronic diseases,such as knee osteoarthritis(KOA).Food intake is important because it can be controlled.However,the causal relationship of food intake and KOA still remain unclear.To ident...Lifestyle is related to many chronic diseases,such as knee osteoarthritis(KOA).Food intake is important because it can be controlled.However,the causal relationship of food intake and KOA still remain unclear.To identify the relationship between food intake and KOA and to screen relevant targets.First,we performed two-sample Mendelian randomization(MR)analysis.A total of 16 kinds of food intake datasets were included,the inverse variance-weighted analysis showed that the KOA was negatively correlated with cereal intake(odds ratio(OR)0.48;95%CI 0.35-0.68;P=1.98×10−5).Second,potential drug targets of KOA in plasma were explored,secreted protein acidic and rich in cysteine(SPARC,or osteonectin),SPARC,Cwcv,and Kazal-like domains proteoglycan 2(SPOCK2)as the causal protein for plasma with KOA,and increased SPOCK2(OR 0.84;95%CI 0.77-0.92;P=5.52×10−5),decreased the risk of KOA.Integrated transcriptomic analysis(P=0.0285)and in vivo(P=0.0395)showed consistent results.Finally,by metabolomics analysis and molecular docking,seven co-expressed small molecules were detected in cereal and were bound to SPOCK2.Our findings indicate the cereal intake was negatively correlated with KOA,and support the SPOCK2 as a novel potential target for cereal intake in KOA.Our study will provide a clinical dietary guidance for KOA patients and a theoretical basis for the development of novel,side-effect-free drugs for KOA.展开更多
基金supported by the Key Laboratory of Automotive Power Train and Electronics(Hubei University of Automotive Technology)(ZDK1201505)Auto Parts TechnologyHubei Province Collaborative Innovation Project(2015XTZX04).
文摘The intake system of a racing engine plays a crucial role in determining its performance,particularly in terms of volumetric efficiency,power output,and throttle response.According to Formula Society of Automotive Engineers(FSAE)regulations,the engine intake systemmust incorporate a 20mmdiameter flow-limiting valve within the intake manifold.This restriction significantly reduces the airflow into the engine,leading to a substantial drop in power output.To mitigate this limitation,the intake system requires a redesign.In this study,theoretical calculations and one-dimensional thermodynamic simulations are employed to determine the optimal parameters for the intake system.A numerical simulation of the intake system’s flow field is then conducted to refine its structure and layout.Finally,experiments are performed on an engine equipped with the optimized intake system,and its feasibility is evaluated based on experimental results.Thefindings indicate that the maximumengine torque increases from56.36 to 59.91 N⋅m,while the maximum power output rises from 59.16 to 63.94 kW.To further enhance performance and adaptability across different competitions,a variable-length intakemanifold control system is also designed,improving both power delivery and overall operational stability of the racing car.
基金Guangxi colleges and universities young and middle-aged teachers basic ability improvement project,which is called“Optimization Analysis of Gasoline Engine Performance Based on the Inlet Throttle for FSC Intake System”(No.2018KY0654)。
文摘In some competitions the rules clearly state that all participating cars must install a restrictor valve structure in the intake system of the engine.The intake air volume of the engine is considerably affected due to the existence of such a valve.Indeed,a small interface diameter through which gas flows can lead to considerable flow resistance and loss.In this study,a four-cylinder engine for FSC racing is analyzed using a combined method based on numerical simulation and experiments.The analysis reveals that the main factors affecting the intake air volume are the intake manifold and the volume of the resonance chamber.The influence of such factors is assessed using a single variable method and an optimal model and parameters are obtained accordingly.Comparison of different results show that the maximum torque for the optimized system is increased from the original 42.6 N·m to 46.9 N·m,thus demonstrating an increase of 10.6%.These findings provide a theoretical basis for the design of the intake system and the improvement of engine performance.
基金“Strategic Cooperation of Science and Technology between Nanchong City and Southwest Petroleum University 2018” Special Fund Project,China(Nos.18SXHZ0030,18SXHZ0054)
文摘To find out and improve the flow characteristics inside the intake system of cylinder head,the application of computational fluid dynamics(CFD)in the evaluation and optimization of the reconstructed intake system based on slicing reverse method was proposed.The flow characteristics were found out through CFD,and the velocity vector field,pressure field and turbulent kinetic energy field for different valve lifts were discussed,which were in good agreement with experimental data,and the quality of reconstruction was evaluated.In order to improve its flow characteristic,an optimization plan was proposed.The results show that the flow characteristics after optimization are obviously improved.The results can provide a reference for the design and optimization of the intake system of cylinder head.
文摘The goal of this study is to develop an airflow meter sensor for vehicle intake system detection in internal combustion engines. The study uses micro-electromechanical process technology to develop a hot-film flow meter with an alumina substrate and platinum film heater;the hotline method is used to create a micro airflow anemometry meter sensor relying on variations in resistance of the platinum film corresponding to different wind velocity at the set temperatures. The micro-sensor is less bulky and simpler structure than ordinary meters, and its small size enables it to provide good sensitivity and measurement precision. The alumina plate used in this study is produced by polishing an alumina substrate, a platinum film is then deposited on the plate to complete the micro-heater used in the sensor. Resistance on the sensor side varies as gas flows through the sensor, and the instrument determines airflow velocity on the basis of the changes in resistance caused by gas flow differences. Airflow velocity form 10 m/s to 60 m/s are used to test. Resistance displays a regular slope, indicating the relationship between airflow velocities varies remain predictable throughout the sensing range. Therefore, the sensor can achieve its airflow measurement purpose completely.
文摘Industry and energy continue to require piston engines(PICE)at a high level worldwide.Therefore,science and technology must urgently work on improving the PICE working cycle.Improving the quality of the intake process of theworking fluid into the cylinder is one of the most effective ways to improve the operational performance of PICE.The purpose of the study was to assess the impact of various cylinder head(CylH)designs on the gas-dynamic and heat-exchange qualities of air flows within an engine model’s intake system.Three different CylH designs were studied:the basic configuration and upgraded cylinder heads with a square valve and a square valve port.These designs are innovative.Laboratory conditions were used to conduct the studies for stationary air flow.The experiments covered the range of Reynolds numbers from 8500 to 96,000.The intake system’s gas dynamics and heat transfer were determined using the thermal anemometry method,which was based on constant-temperature hot-wire anemometers.It has been established that the use of upgraded CylHs causes an increase in the turbulence number of flow by an average of 13.5%.Additionally,itwas found that the increase in the turbulence number of flowin the cylinder is about 19%when installing new CylH designs.It was shown that therewas an increase in the heat transfer coefficient in the intake pipe by 10%–40%when installing modernized CylH designs in the intake system.The article focused on the problems of increasing the turbulence level and intensifying the heat transfer of stationary air flow in the intake system,specifically in PICEs.The study’s findings are novel in the areas of applied gas dynamics and PICEs.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 51106110）.
文摘Based on energy conservation equation and Darcy＇s law, a model of beach well infiltration intake system applied in a seawater source heat pump system was established. The model consists of the seawater seepage and the heat transfer process. A porous medium model in a software named FLUENT was applied to simulate the seepage and the heat transfer process. This model was also validated by field experiment conducted on the seashore in Tianjin, China. The maximum relative error between simulation results and experimental results was 2.1% （less than 5%）, which was acceptable in engineering applica- tion. The porosity and coefficient of thermal conductivity of the aquifer soil were determined to be 0.49 W/（m. K） and 1.46W/（m.K）, respectively in the simulation. In addition, the influencing factors of pumping water of beach well were also analyzed. The pumping water was found to increase when the distance between the beach well and the impervious boundary becomes longer, when the distance between the beach well and the supplying water source shortens, when the diameter of the beach well enlarges, and the drawdown enlarges.
基金Supported by a fellowship of the 'FundacióPrivada Institut D' investigacio Biomédica de Bellvitge (IDIBELL) partially funded by the ISCⅢnetwork (RCESP C03/09) Spain and ECNIS Network from the 6FP of the EC
文摘AIM： To study the association between nitrite and nitrosamine intake and gastric cancer （GC）, between meat and processed meat intake, GC and oesophageal cancer （OC）, and between preserved fish, vegetable and smoked food intake and GC. METHODS： In this article we reviewed all the published cohort and case-control studies from 1985-2005, and analyzed the relationship between nitrosamine and nitrite intake and the most important related food intake （meat and processed meat, preserved vegetables and fish, smoked foods and beer drinking） and GC or OC risk. Sixty-one studies, 11 cohorts and 50 case-control studies were included. RESULTS： Evidence from case-control studies supported an association between nitrite and nitrosamine intake with GC but evidence was insufficient in relation to OC. A high proportion of case-control studies found a positive association with meat intake for both tumours （11 of 16 studies on GC and 11 of 18 studies on OC）. A relatively large number of case-control studies showed quite consistent results supporting a positive association between processed meat intake and GC and OC risk （10 of 14 studies on GC and 8 of 9 studies on OC）. Almost all the case-control studies found a positive and significant association between preserved fish, vegetable and smoked food intake and GC. The evidence regarding OC was more limited. Overall the evidence from cohort studies was insufficient or more inconsistent than that from case-control studies.CONCLUSION： The available evidence supports a positive association between nitrite and nitrosamine intake and GC, between meat and processed meat intake and GC and OC, and between preserved fish, vegetable and smoked food intake and GC, but is not conclusive.
基金supported by the National Natural Science Foundation of China(No.51204124)the China Postdoctoral Science Foundation(No.2012M511610)the Scientific Research Foundation of Wuhan Institute of Technology(No.14125041)
文摘To eliminate the shrinkage porosity in low pressure casting of an A356 aluminum alloy intake manifold casting, numerical simulation on fi lling and solidifi cation processes of the casting was carried out using the ProCAST software. The gating system of the casting is optimized according to the simulation results. Results show that when the gating system consists of only one sprue, the fi lling of the molten metal is not stable; and the casting does not follow the sequence solidifi cation, and many shrinkage porosities are observed through the casting. After the gating system is improved by adding one runner and two in-gates, the fi lling time is prolonged from 4.0 s to 4.5 s, the fi lling of molten metal becomes stable, but this casting does not follow the sequence solidifi cation either. Some shrinkage porosity is also observed in the hot spots of the casting. When the gating system was further improved by adding risers and chill to the hot spots of the casting, the shrinkage porosity defects were eliminated completely. Finally, by using the optimized gating system the A356 aluminum alloy intake manifold casting with integrated shape and smooth surface as well as dense microstructure was successfully produced.
基金Project supported by of the National Marine Public Welfare Research Projects of China(Grant No.201005002)supported by the Hong Kong Polytechnic University(Grant No.H-ZG68)
文摘A 3-D numerical model for pump intake is established based on the Navier-Stokes equations with the RNG k-ε turbulence model and the VOF method to simulate the free surface. The applicability of the proposed model is validated by a test case of non-symmetric pump-intake bay. The predicted locations, structures and shapes of all vortices are in good agreement with those observed in experiments, though with some differences in vorticity strengths. The flow pattern and the efficiency of five types of pump intake systems are studied. The discharge and the velocity tmiformity of the intake system are used as indices to evaluate its performance.
文摘This paper presents a KIVA-3 code based numerical model for three-dimensional transient intake flow in the intake port-valve-cylinder system of internal combustion engine using body-fitted technique, which can be used in numerical study on internal combustion engine with vertical and inclined valves, and has higher calculation precision. A numerical simulation (on the intake process of a two-valve engine with a semi-sphere combustion chamber and a radial intake port) is provided for analysis of the velocity field and pressure field of different plane at different crank angles. The results revealed the formation of the tumble motion, the evolution of flow field parameters and the variation of tumble ratios as important information for the design of engine in-take system.
基金The Meath Foundation of Tallaght University Hospital,No.117/2020.
文摘BACKGROUND A progressive reduction in the secretion of pancreatic enzymes in patients with chronic pancreatitis(CP)results in malabsorption and ultimate malnutrition.However,the pathogenesis of malnutrition is multifactorial and other factors such as chronic inflammation,alcohol excess and poor dietary intake all contribute.Patients may restrict their dietary intake due to poor appetite or to avoid gastrointestinal symptoms and abdominal pain.Whilst up to half of patients with chronic pancreatitis are reportedly malnourished,the dietary intake of patients with CP is relatively understudied and has not been systematically reviewed to date.AIM To perform a systematic review and meta-analysis of the dietary intakes of patients with CP compared to healthy controls,and to compare the dietary intake of patients with alcohol-related CP and non-alcohol-related CP.METHODS A systematic literature search was performed using EMBASE,MEDLINE,and Cochrane review on studies published between 1946 and August 30th,2019.Adult subjects with a diagnosis of CP who had undergone dietary assessment were included in the systematic review(qualitative analysis).Studies on patients with other pancreatic diseases or who had undergone pancreatic surgery were not included.Studies comparing the dietary intake of patients with CP to that of healthy controls were included in the meta-analysis(quantitative analysis).Metaanalysis was performed using Review Manager 5.3.Newcastle Ottawa Scale(NOS)was used to assess quality of studies.RESULTS Of 6715 studies retrieved in the search,23 were eligible for qualitative analysis while 12 were eligible for quantitative analysis.In the meta-analysis,the total energy(calorie)intake of patients with CP was similar to that of healthy controls[mean difference(MD):171.3;95%confidence interval(CI):-226.01,568.5;P=0.4],however patients with CP consumed significantly fewer non-alcohol calories than controls[MD:-694.1;95%CI:-1256.1,(-132.1);P=0.02].CP patients consumed more protein,but carbohydrate and fat intakes did not differ significantly.Those with alcohol-related CP consumed more mean(standard deviation)calories than CP patients with a non-alcohol aetiology[2642(1090)kcal and 1372(394)kcal,respectively,P=0.046],as well as more protein,fat,but not carbohydrate.CONCLUSION Although patients with CP had similar calorie intake to controls,studies that analysed the contribution of alcohol to energy intake showed that patients with CP consumed fewer non-alcohol calories than healthy controls.A high calorie intake,made up to a large degree by alcohol,may in part contribute to poor nutritional status in CP.
文摘Underground mines in Arctic and Subarctic regions require the preheating of mine intake air during winter.The cold fresh air of those remote areas can be as severe as40℃ and commonly needs to be heated to around+3℃.This extensive amount of heating is usually provided by employing large-size air heaters,fueled by diesel,propane,natural gas,or heavy oil,leading to high energy costs and large carbon footprints.At the same time,the thermal energy content of a diesel generator sets(gen-sets)exhaust is known to be one-third of the total heating value of its combusted fuel.Exhaust heat recovery from diesel gen-sets is a growing technology that seeks to mitigate the energy costs by capturing and redirecting this commonly rejected exhaust heat to other applications such as space heating or pre-heating of the mine intake air.The present study investigated the possibility of employing a simple system based on off-theshelf heat exchanger technology,which can recover the waste heat from the exhaust of the power generation units(diesel gen-sets)in an off-grid,cold,remote mine in Canada for heating of the mine intake air.Data from a real mine was used for the analysis along with environmental data of three different location-scenarios with distinct climates.After developing a thermodynamic model,the heat savings were calculated,and an economic feasibility evaluation was performed.The proposed system was found highly viable with annual savings of up to C$6.7 million and capable enough to provide an average of around 75%of the heating demand for mine intake air,leading to a payback period of about eleven months or less for all scenarios.Deployment of seasonal thermal energy storage has also been recommended to mitigate the mismatch between supply and demand,mainly in summertime,possibly allowing the system to eliminate fuel costs for intake air heating.
文摘In order to improve the cold start performance of heavy duty diesel engine, electronically controlling the preheating of intake air by flame was researched. According to simulation and thermodynamic analysis about the partial working processes of the diesel engine, the amount of heat energy, enough to make the fuel self ignite at the end of compression process at different temperatures of coolant and intake air, was calculated. Several HY20 preheating plugs were used to heat up the intake air. Meanwhile, an electronic control system based on 8 bit micro controller unit (MCS 8031) was designed to automatically control the process of heating intake air. According to the various temperatures of coolant and ambient air, one plug or two plugs can automatically be selected to heat intake air. The demo experiment validated that the total system could operate successfully and achieve the scheduled function.
文摘Food based approach can prove effective in improving access and availability of nutrients from foods required for daily life where most of the people depend on agriculture for their livelihood. A study on feasibility of Farming Systems for Nutrition (FSN) approach was undertaken from 2013 to 2018 in a few villages of Koraput district, Odisha state and Wardha district, Maharashtra state in India. Interventions were done to increase crop diversity, intercropping of pulses and cereals, promotion of seasonal vegetables and fruits along </span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">with </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">nutrition awareness. The endline survey showed increase in production diversity leading to improved household dietary diversity. This paper demonstrates the impact of FSN interventions on household nutrient intake. The results show that the intake of nutrients like protein, vitamin C, iron and calcium increased significantly in Koraput and all the nutrients including energy and vitamin A increased significantly in Wardha. The evidence shows that Farming System for Nutrition approach improves individual nutrient intake which in the long run can address the problem of undernutrition.
文摘Equilibrium function in the cerebellum （vestibulo-cerebellar system） can deteriorate under the influence of alcohol. In the Romberg posture, the center of gravity, which was measured every 50 ms by stabilometry, appeared to shift with alcohol ingestion. In the previous study, a locus in the center of gravity （stabilogram） was converted to values of statistical indices such as area of sway, total locus length, sparse density, and locus length per unit area, although these indices could not always distinguish between the stabilograms sampled from seven healthy young males in sober and intoxicated states. This measurement was made with an AMTI force plate. In this study, ＂translation error＂ was estimated in a d-dimensional embedding space in order to compare stabilograms recorded before and after the ingestion of doubly diluted brandy in 30 s （1 ≤ d ≤ 10）. The authors succeeded in validating stochastic differential equations as a mathematical model of the body sway. Although the postural control system shows different patterns in the lateral and anterior-posterior directions, the randomness in the model was preserved after alcohol intake and significantly increased in the medial/lateral direction. Visual information referred by the postural conlrol system when standing might be interfered by the effects of intoxication, which was regarded as disturbance. The possibility of detecting alcohol-ingestion-induced reduction of the equilibrium function and its recovery process are also suggested in this paper. This method is considered to be useful to diagnose the disorders of the vestibulo-cerebellar system.
文摘Seasonal and sexual variations as well as the effect of dry feed supplement on total drinking water intake and its utilization were observed in mithun （Bosfrontalis） - a semi-wild animal found in North Eastern Hill Region （NEHR） of India. In a completely randomized design, twelve adult mithuns （B. frontalis） as per their sex and body weight were assigned in two different rearing systems （free grazing and free grazing with dry concentrate feed supplementation）, and ten growing male mithuns as per their body weight assigned in two different levels of dry concentrate feed supplementation （1.o kg and 2.0 kg dry concentrate feeds on green forage based diet） and in two different seasons （summer and winter）. It was observed that the environmental temperature had a significant effect on drinking water intake by mithuns. Drinking water consumption （per unit of body weight） was significantly （P 〈 0.05） higher in summer than in winter. Supplementation of concentrate feed on free grazing animals resulted in increase in water consumption. Total water consumption （drinking as well as performed water） was found to be 15.18 litres per 100 kg body weight by growing mithun. Feed dry matter and digestible nutrient intakes by growing mithun were observed to be increased with the increase of supplementation of dry concentrate feed. Roughage to concentrate ratio did not affect the nutrient digestibility. Mithun calves drank an average of 4.30 litres water for each kg of dry matter intake. Metabolic water was significantly （P〈0.01） increased with the increase of supplementation of concentrate feed whereas water turn over, which depends upon the body weight of the animals, did not differ significantly on offering of lower or higher level of dry feed. Faecal water loss of growing mithun was decreased with the increase in intake of concentrate feed and was estimated to be 33 - 46 % of total water intake. Excretion of water through faeces of mithun was about 3.8 % of body weight. It could, therefore, be inferred that water intake by mithun varied with seasons, rearing systems and dry feed consumption. As far as the water nutrition is concerned, it is needed to give an attention while feeding mithun in summer with dry feed supplementation under semi-intensive system of rearing.
基金supported by the National Key R&D Program of China (2020YFA0803800)the National Natural Science Foundation of China (31971097)。
文摘Magnesium plays a critical role in the human's life activities and energy metabolism. This study aimed to evaluate the magnesium status of athletes via a systematic review of cross-sectional studies. A comprehensive systematic search was conducted in PubMed, Web of Science, SPORTDiscus, Cochrane Library electronic databases, and other sources before April 5, 2021. Fourteen studies were included in the systematic review, involving 855 athletes and 521 control subjects. Serum magnesium concentration was significantly lower in athletes(mean difference(MD):-0.04 mmol/L;95% confidence interval(CI):-0.06 to-0.01;P = 0.02)in spite of significantly higher dietary magnesium intake(MD: 51.72 mg/day;95% CI: 14.62 to 88.83;P = 0.006). Meta-analysis showed that 24-h urinary magnesium excretion in athletes was significantly higher than that in the untrained population(MD: 0.76 mmol/day;95% CI: 0.11 to 1.41;P = 0.02). Despite higher total dietary magnesium intake, athletes generally have lower serum magnesium concentration and higher 24-h urinary magnesium excretion, demonstrating that the magnesium requirement of athletes is higher than the untrained population. It is necessary to carry out a dietary assessment and nutrition counseling to help athletes adopt proper diets to meet their nutritional needs in exercise.
文摘The hydraulic and sediment deposition problems in the water intake system of a pumping house were studied by physical model. The experimental results of different working cases indicate that the sediment depositions at the gates, stilling basin and culverts are very few when the system was normally operated, but in the forebay of pumping house, especially in the pumping house for living water, the amount of sediment deposition sometimes is considerably large. At the front of the entry of pumping house for living water, installing a set of oblique pipes can prevent the coarse grains to enter it, the deposition amount will obviously decrease.
文摘An monitoring and earlywarning system is proposed for marine organisms and the cause of water intake blockage is analyzed. Based onthe intelligent sensing technology, computer software and hardware technology and digital signal processing technology, the buoy monitoring platformsystem is developed by internet of things technology, cloud computing and the application of large data. Remote realtime monitoring of aquatic organisms and foreign bodies is realized based on underwater acoustic detection and low light imaging technology. Data processing center is established to store, analyze and process monitoring information and display it in real time, and provide emergency decision support. Through development and test of relevant key equipments, the reliability of cold source system of nuclear power plants is improved, which effectively reduces theinfluence of marine biological invasion on security and economic operation of the units.
基金supported by the National Natural Science Foundation of China(82072432)Scientific Research and Innovation Platform for Intelligent and Precise Treatment of Bone and Joint Diseases in Shaanxi Province(2024PT-13)Key Project of Shaanxi Provincial Natural Science Foundation(2024JC-ZDXM-55).
文摘Lifestyle is related to many chronic diseases,such as knee osteoarthritis(KOA).Food intake is important because it can be controlled.However,the causal relationship of food intake and KOA still remain unclear.To identify the relationship between food intake and KOA and to screen relevant targets.First,we performed two-sample Mendelian randomization(MR)analysis.A total of 16 kinds of food intake datasets were included,the inverse variance-weighted analysis showed that the KOA was negatively correlated with cereal intake(odds ratio(OR)0.48;95%CI 0.35-0.68;P=1.98×10−5).Second,potential drug targets of KOA in plasma were explored,secreted protein acidic and rich in cysteine(SPARC,or osteonectin),SPARC,Cwcv,and Kazal-like domains proteoglycan 2(SPOCK2)as the causal protein for plasma with KOA,and increased SPOCK2(OR 0.84;95%CI 0.77-0.92;P=5.52×10−5),decreased the risk of KOA.Integrated transcriptomic analysis(P=0.0285)and in vivo(P=0.0395)showed consistent results.Finally,by metabolomics analysis and molecular docking,seven co-expressed small molecules were detected in cereal and were bound to SPOCK2.Our findings indicate the cereal intake was negatively correlated with KOA,and support the SPOCK2 as a novel potential target for cereal intake in KOA.Our study will provide a clinical dietary guidance for KOA patients and a theoretical basis for the development of novel,side-effect-free drugs for KOA.
